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This study aimed to describe longitudinal testicular volume (TV) data of Nellore bulls by using nonlinear mixed models. Dataset consisted of 2,294 TV measurements from 505 bulls with ages ranging from 563 to 4,307 days. Nine nonlinear models were evaluated: Brody, Gompertz, Hill, Logistic I and II, Meloun, Michaelis-Menten, Mitscherlich and von Bertalanffy. Goodness of fit was evaluated by Akaike's information criterion (AIC), Bayesian information criterion (BIC), adjusted R2, percentage of convergence, error sum of squares (ESS), mean absolute deviation (MAD), and average prediction error (APE). These criteria were used to select the best model, then the absolute growth rate (AGR) for TV was estimated by the first derivate of the adjusted model related to time ( ∂ Y / ∂ t ). The values of adjusted R2, ESS, MAD and APE were similar among models. Percentage of convergence was higher for the Logistic I (76.8%), Logistic II (75.5%) and Mitscherlich (78.6%) models, but Logistic I and II showed the lowest values of AIC and BIC, indicating a better fit, so the Logistic I model was chosen for subsequent analyses. The TV growth occurred at a high rate until the inflection point, which was estimated at approximately 22 months of age; it stabilized and reached a plateau at approximately 2,500 days of age. This may suggest that TV is more related to sexual maturity than precocity. Additionally, the Logistic I model was used to estimate the growth curve and the AGR of the testicular length and width. As a result, testicular length increased at a higher rate than testicular width until approximately 1,600 days of age, indicating that the testes become longer with increasing age.

During the last decade, environmental toxicants have been considered a potential cause for declining sperm quality. Toxic metals are not easily degraded and may accumulate along the food chain, which may negatively impact the semen quality of animals. In this framework, we conducted a meta-analysis to determine whether exposure to Al, As, Cd, Cr, Co, Cu, Fe, Mg, Mn, Hg, Ni, and Pb affects sperm and andrological parameters of domestic ruminants. We extracted 217 independent comparisons from 39 published articles selected from PubMed, Web of Science, and Scopus. Our findings showed that metal exposure reduced sperm viability (d

This study aimed to describe the testicular growth curve in Mangalarga Marchador stallions fitting nonlinear models to data of total scrotal width (TSW) and testicular volume (TV). A cross-sectional study was conducted with 120 stallions, aging from 1.75 to 21.93 years. The parameters of nonlinear models (Brody, Gompertz, Hill, Logistic I and II, Meloun I and II, Michaelis-Menten, Mitscherlich, and von-Bertalanffy) were estimated by Gauss-Newton iterative process. Goodness of fit was evaluated by the corrected Akaike (AICc) and Bayesian (BIC) information criteria, adjusted R2, error sum of square, mean absolute deviation and average prediction error. Based on the goodness of fit, the Logistic I model fitted better for TSW while Logistic II fitted better for TV growth curve. The inflection point (IP) of TSW growth was estimated in 5.23 cm at 0.76 years; the IP of TV growth was estimated in 139.36 cm3 at 2.57 years. The TV growth curve reached a plateau later than TSW growth curve, mainly because testicular height maintains growth for a longer period. In addition, there were moderate and positive correlations between whiter height and TSW and TV (r = 0.51 and r = 0.53, respectively). Findings suggest that TV is more associated with sexual maturity than sexual precocity. In addition, the moderate and positive correlations between whiter height and TSW and TV indicate that testicular traits can be included in selection programs of Mangalarga Marchador stallions with the same relevance as the morphometric traits.

This study was conducted to characterize the daily profile of testosterone secretion and its mean concentrations in the four seasons as well as to evaluate the semen characteristics and testicular biometry of Mangalarga Marchador stallions throughout the year in a tropical region. Three stallions were submitted to semen collections and evaluation of testicular biometry every 14 days along a year. Blood samples were collected once at the middle of each season, in a 20-min interval during 24 hr in order to evaluate the testosterone secretion profiles among seasons. Testosterone concentrations along the day were higher at the beginning of the afternoon (from 12:00 to 15:00 hr), but a circadian secretion was not clearly observed. Mean testosterone concentrations did not differ among seasons (p > .05), but a pattern of secretion along the day showed variations with higher concentrations in the afternoon during the winter. Ejaculate volume was higher during summer; however, sperm motility decreased in summer and spring. Total sperm in ejaculate, sperm morphology and testicular biometry kept constant along the year showing no differences among the seasons. The results demonstrated that in a tropical region, reproductive aspects of stallions did not show a clearly defined seasonal variation, and months of autumn and winter were not unsuitable for reproduction of the males.

This study aimed to evaluate the correlation between testicular biometry and semen variables, as well as, to relate testicular variables to the probability of selecting Nellore bulls with desirable sperm morphology when conducting breeding soundness evaluations (BSE). A total of 2055 BSEs from 506 bulls comprised the dataset. Biometric variables evaluated were: scrotal circumference, testicular volume, width, length, ratio and eccentricity; and semen variables were sperm motility, major sperm defects, minor sperm defects and normal sperm. Data of testicular biometry were correlated with data for semen variables using the Pearson’s correlation assessment. Effects of testicular variables in selecting for sperm morphology of bulls in the BSE were evaluated by logistic regression. Scrotal circumference, testicular volume, length and width were positively correlated to sperm motility (0.18 to 0.19) and normal sperm (0.24 to 0.27) and negatively correlated with values for major defects (−0.24 to −0.27), but for testicular ratio and eccentricity there were coefficients near zero for all semen traits. Testicular ratio and eccentricity were not suitable for predicting the probability of selecting a bull based on semen variables using the BSE, but scrotal circumference, testicular volume, length and width were highly significant (P

This study aimed to assess characteristics of bovine cryopreserved sperm and evaluate its relation to field fertility in fixed-time artificial insemination (FTAI). Semen samples of 16 bulls were used to inseminate 811 Nellore cows, and four of these bulls were also used to inseminate 101 Nellore heifers. Samples of the same ejaculate used for FTAI from each bull were analysed in the laboratory after thawing. Sperm motility and vigour were subjectively assessed by light microscope, and integrity of the plasma and acrosome membranes, and H2 O2 production were evaluated by flow cytometer. Relation among sperm characteristics and pregnancy rate of cows and heifers were evaluated by univariate and multivariate logistic regression. Subjective sperm motility and vigour did not affect the probability of pregnancy in cows or heifers. In univariate analysis for pregnancy in cows, sperm traits related to acrosome injury positively affected probability of pregnancy mainly when associated with plasma membrane integrity; H2 O2 production seems to be less important than plasma membrane integrity in affecting probability of pregnancy. In multivariate analysis, sperm traits related to injured acrosome positively affected probability of cow and heifer pregnancies while intact acrosome was negatively related to cow pregnancy. Intact plasma membrane and high H2 O2 production were positively related to cow pregnancy but negatively related to heifer pregnancy. Results suggest that a capacitation-like status of the acrosome may benefit probability of pregnancy in cows.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Este trabalho foi realizado com o objetivo de comparar os efeitos de diferentes crioprotetores e aditivos na criopreservação do sêmen equino sobre a viabilidade espermática in vitro pós-descongelamento. Para tanto, foram designados dois experimentos (E). No E1 objetivou-se comparar o efeito do glicerol (GLIC) e da dimetilformamida (DMFA), associados ou não, sobre a viabilidade espermática in vitro pós-descongelamento, o que conferiu quatro grupos experimentais: glicerol a 5 % (GLIC), dimetilformamida a 5 % (DMFA), dimetilformamida a 3% associada ao glicerol a 2 % (DG) e o tratamento controle, composto pelo diluente comercial Botu-Crio® (BC). Já no E2 objetivou-se avaliar o efeito do congelamento de sêmen de garanhões em diluente contendo glicerol e/ou dimetilformamida, associados à antocianina (ATC) e/ou colesterol carreado por ciclodextrina (CCC). Para tanto, os ejaculados foram congelados em dez diferentes tratamentos, de acordo com as associações entre crioprotetores e aditivos. As amostras de ambos os experimentos foram avaliadas mediante teste de termo-resistência (TTR) e por meio de citometria de fluxo quanto à integridade de membrana plasmática e acrossomal, potencial mitocondrial, produção de peróxido de hidrogênio intracelular e peroxidação lipídica da membrana plasmática; a avaliação quanto à organização da bicamada lipídica só foi realizada no E1. Os melhores resultados obtidos no TTR do E1 foram referentes aos tratamentos DMFA e DG (p0,05). A maior proporção de células com integridade de membrana plasmática e acrossomal foi observada nos tratamentos DMFA e BC (p0,05). Em relação ao E2, não houveram interações entre crioprotetores e diluentes para maioria das características estudadas, sendo as comparações realizadas entre grupos de tratamentos. Entre os crioprotetores, o grupo DMFA apresentou os melhores resultados quanto à motilidade espermática durante o TTR, seguido do grupo DG (p0.05). The highest proportion of cells with plasma and acrosomal membrane integrity was observed in DMFA and BC treatments (p0.05). About E2 there were no interactions between cryoprotectants and diluents for most traits, with comparisons made between treatment groups. Among the cryoprotectants, DMFA group showed the best results on the TTR, followed by DG group (p

Lopes E. de P., Pinho R.O., Siqueira J.B., Rocha A.N., Pereira J.V.T. do N., Martins L.F., de Freitas B.W. & Guimarães J.D. [Correlation of factors which affect reproductive eficiency of Mangalarga Marchador mares in embryo transfer programs]. Correlação dos fatores que interferem na eficiência reprodutiva de éguas Mangalarga Marchador em programas de transferência de embriões. Revista Brasileira de Medicina Veterinária, 35(1):69-75, 2013. Departamento de Medicina Veterinária, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, Campus Universitário, Viçosa, MG 36570-000, Brasil. E-mail: jhonatavet@yahoo.com.br The objective of this study was to verify the relationship of some reproductive features with embryo recovery in donor mares and recipients reproductive in embryo transfer programs. There were used 209 Mangalarga Marchador mares from five to 20 years of age, accompanied during six reproductive seasons, evaluating some reproductive features such as foal heat, embryo age, synchrony between donor and recipient mares, among others. There were 1,140 flushing procedures with 72.8% of recovery rate. Significant correlation was observed only in embryo recovery with the size of the first follicle (r = 0.08) and with artificial insemination of the donor in pre-ovulatory phase (r = 0.11), beyond the mares status with synchrony between donor and recipient (r = 0.06), although the correlation values have been very low. The low correlations obtained between the studied features have small influence over pregnancy rates in an equine embryo transfer program. The adoption of a higher flexibilization in the ovulatory synchronism between donor and recipient mares optimizes the use of recipient mares, thus reducing costs and facilitating management of horse breeding farms., O objetivo deste estudo foi verificar a relação de algumas características reprodutivas com a recuperação embrionária em éguas doadoras e status reprodutivo de receptoras em programas de transferência de embriões. Foram utilizadas 209 éguas da raça Mangalarga Marchador, de cinco a20 anos de idade, acompanhadas durante seis estações reprodutivas, avaliando-se algumas características reprodutivas como utilização do cio do potro, idade do embrião, sincronia entre doadora e receptora, entre outras. Totalizou-se 1140 coletas com recuperação de 72,8%. Foi observada correlaçãosignificativa apenas da recuperação embrionária com o tamanho do primeiro folículo (r = 0,08) e com inseminação artificial da doadora na fase pré- -ovulatória (r = 0,11), além do status da égua com a sincronia entre doadora e receptora (r = 0,06), embora os valores de correlação tenham se mostrado muito baixos. As baixas correlações existentes entre as características possuem baixa influência sobre as taxas de prenhez obtidas em um programa de transferência de embriões eqüinos. A adoção de maior flexibilização na sincronia de ovulação entre doadoras e receptoras proporciona otimização no uso de receptoras, redução de custos e melhorias no manejo das fazendas.

Conselho Nacional de Desenvolvimento Científico e Tecnológico The aim of this study was to evaluate the reproductive and physiological parameters of Mangalarga Marchador stallions raised in Viçosa, Minas Gerais, Brazil during the four seasons and maintained semi-stabled. Thus, the study was conducted in a period of ten months (April 2009 to March 2010), using three stallions between 7 and 15 years of age and submitted to semen collections at intervals of 14 days for evaluation of physical and morphological semen parameters, complementary tests and cooling, and quantification of total soluble proteins present in seminal plasma. The physiological parameters measured were: respiratory and cardiac frequencies and rectal temperature at weekly intervals in the morning and afternoon. Testicular biometics and echotexture were measured before semen collection and, to determine the serum testosterone, the blood was collected every season at 20 minute intervals during a period of 24 hours. In relation to the seminal characteristics, a progressive increase in the volume with and without gel between autumn and summer was observed (p0.05) between seasons and showed an average of 14.3 mg/mL. Testosterone secretions did not show a circadian pattern, but the highest concentration occurred between 10 and 14 hours, so that the largest average concentrations were observed in winter and summer (p0.05) and testicular echotexture was higher during summer (p 0,05) entre as estações climáticas e apresentou uma média de 14,3 mg/mL. A secreção de testosterona não apresentou um padrão circadiano, porém as maiores concentrações ocorreram de 10:00 às 14:00, sendo que as maiores concentrações foram observadas no inverno e verão (p < 0,05). O volume testicular não foi influenciado pela sazonalidade (p > 0,05) e a ecotextura testicular foi maior no verão (p < 0,05). Concluiu-se que a estação do ano exerce efeito sobre algumas características seminais, principalmente quanto aos aspectos físicos do sêmen e resistência ao processo de resfriamento do mesmo, além da ecotextura testicular e da secreção média de testosterona, de forma que a influência sobre estas últimas não apresentou correlações importantes com as demais características estudadas.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Os diluentes à base de gema de ovo e leite têm sido amplamente utilizados na preservação seminal, entretanto, estes apresentam riscos sanitários pela transmissão de patógenos. Portanto, novos estudos têm surgido na busca por um diluente de origem vegetal, capaz de assegurar a qualidade espermática e ao mesmo tempo eliminar o risco de contaminação apresentado por aqueles de origem animal. Em função do exposto, uma revisão meta-analítica foi conduzida para determinar o efeito da água de coco como diluente seminal para a preservação de espermatozoides de pequenos ruminantes. Quatro bases de dados foram utilizadas para realizar as buscas bibliográficas, sendo estas PubMed, Science Direct, Scopus e Web of Science. Foram obtidas 88 comparações independentes dos 09 estudos selecionados, conforme os critérios de seleção deste estudo. A diferença média ponderada (DMP) entre os tratamentos com água de coco (diluentes com inclusão de água de coco) e tratamentos controle (diluentes sem adição de água de coco) foi avaliada por meio da utilização de um modelo de efeitos aleatórios. Para avaliar a heterogeneidade, foram realizadas análises de meta-regressão e subgrupo, utilizando como covariável: tipo de água de coco, tipo de tratamento controle ao qual a água de coco foi contrastada, tipo de preservação, tempo de preservação e espécie animal. A água de coco resultou em um incremento sobre a variável motilidade total para sêmen resfriado (P < 0,05), ao passo que, para o sêmen fresco e criopreservado, não foi observado qualquer efeito significativo. Para a variável integridade de membrana, observou-se um efeito positivo para sêmen fresco (P < 0,05). Para o sêmen resfriado, foi encontrado um resultado negativo (P < 0,05). O emprego da água de coco como diluente seminal apresentou-se como alternativa viável para a preservação seminal em pequenos ruminantes. Palavras-chave: Água de coco. Diluente. Espermatozoide. Qualidade espermática. Semen extenders based on egg yolk and milk have been widely used in seminal preservation. However, they present health risks due to the transmission of pathogens. Therefore, new studies have emerged seeking for a diluent of vegetable origin, capable of guaranteeing sperm quality and eliminating the risk of contamination presented by that of animal origin. In light of the above, a meta-analytical review was conducted to determine the effect of coconut water as a seminal extender for small ruminants’ sperm preservation. Studies that met the inclusion criteria were retrieved from PubMed, Science Direct, Scopus, and Web of Science. According to the selection criteria of this study, 88 independent comparisons were obtained from the nine studies included in the meta-analysis. The weighted mean difference (WMD) between treatments with coconut water (diluents including coconut water) and control treatments (diluents without the addition of coconut water) was evaluated using the random-effects model of meta-analysis. Heterogeneity was explored by meta-regression and subgroup analysis, performed using as covariate: type of coconut water, types of control treatment to which coconut water was contrasted, type of preservation, preservation time, and animal species. The overall results showed that coconut water elicited a positive effect on the total motility of sperm cells from cooled semen (P < 0.05), while for the fresh and cryopreserved semen no significant effect was observed. In addition, coconut water showed a positive effect on membrane integrity of sperm cells from fresh semen (P < 0.05). On the other hand, for cooled semen, a negative result was found (P < 0.05). Therefore, the use of coconut water as a seminal extender proved to be a viable alternative for seminal preservation in small ruminants. Keywords: Coconut water. Extender. Sperm. Sperm quality.